Safety of dual antiplatelet therapy in daily cardiology practice

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Dual antiplatelet therapy has become the cornerstone of the treatment of acute coronary syndromes with or without stent implantation.1 Although there is consensus about the indication for dual antiplatelet therapy, there is little evidence about the optimal duration of therapy. In patients surviving non-ST-segment-elevation acute coronary syndromes one year of treatment is advised.2 Intuitively, cardiologists prefer longer dual antiplatelet therapy rather than single antiplatelet medication (aspirin alone) in patients with drug-eluting stents when compared with carriers of bare metal stents. Consequently, many patients in the cardiology practice in 2010 are on dual antiplatelet therapy, mainly aspirin and clopidogrel. The only important side effect of dual antiplatelet therapy is increased bleeding in comparison with aspirin alone. This has been established in the large trials with clopidogrel in acute coronary syndromes3,4 as well as in atrial fibrillation.5 Especially in de latter dual antiplatelet therapy has shown to be as hazardous as oral anticoagulation.6 Special attention has been given to the risks of dual antiplatelet therapy in patients awaiting coronary artery bypass surgery. Clopidogrel on top of aspirin has been associated with significantly increased blood loss during coronary surgery when compared with aspirin alone.7 However, this excess bleeding was not significantly associated with an increased risk of reoperation or mortality. Yet, it is generally advised to discontinue clopidogrel five days ahead of coronary surgery. Little is known, however, about the optimal strategy in patients on dual antiplatelet therapy undergoing other forms of surgery such as abdominal surgery, orthopaedic procedures, neurosurgical operations or procedures in other vital organs where bleeding can result in organ loss. Recently, the first guideline on interruption of antiplatelet therapy in general and of dual antiplatelet therapy in particular was published.8 In that guideline, patients with high, medium and low thrombotic risk are identified. In patients with the highest thrombotic risk antiplatelet therapy should be continued, and in the patient with a low thrombotic risk this can be discontinued prior to surgery. …